Angiotensin-converting Enzyme Inhibition Improves the Effectiveness of Transcutaneous Carbon Dioxide Treatment

Abstract

Aim: To study the effect of carbon dioxide (CO₂) therapy on the nitric oxide (NO) pathway by monitoring plasma asymmetric dimethylarginine (ADMA) concentrations. Patients and Methods: Forty-seven hypertensive patients who underwent transcutaneous CO₂ therapy were enrolled. Thirty healthy individuals were recruited for the control group. Blood samples were taken one hour before, as well as one hour, 24 hours and 3 weeks after the first CO₂ treatment. Controls did not undergo CO₂ treatment. Plasma ADMA levels were measured by ELISA. Results: ADMA levels decreased significantly one hour after the first CO2 treatment compared to the baseline concentrations (p=0.003). Significantly greater reduction was found among patients in whom angiotensin converting enzyme inhibitors (ACEIs) were administered (p=0.019). Conclusion: The short- and long-term decrease of ADMA levels suggests that CO₂ is not only a vasodilator, but also has a beneficial effect on the NO pathway. ACE inhibition seems to enhance the effect of CO₂ treatment.